Field pea grain can be included in growing-finishing pig diets as an alternative starch and protein source without affecting growth performance. However, for weaned pigs, there is a concern to include field pea grain in diets because of lower energy digestibility compared with soybean meal and corn grain and the presence of trypsin inhibitors that may affect protein digestion. Processing using heat and friction may reduce trypsin inhibitor activity in field pea grain and increase both energy and protein digestibility; however, its effect on weaned pigs remains unknown. To explore, field pea grain was cold-pelleted (70–75 °C), steam-pelleted (80–85 °C) or single-screw extruded (115 °C). The raw and 3 processed field pea grain samples were included in 4 test diets at 956 g/kg and fed to 8 ileal-cannulated weaned barrows (initial body weight, 11.6 ± 1.2 kg) in a double 4 × 4 Latin square. A N-free diet was also fed to pigs to measure basal endogenous losses of amino acids. Cold-pelleting and extrusion reduced trypsin inhibitor activity (TIA) by 0.8–1.1 mg/g in field pea grain. Cold-pelleting increased (P < 0.05) the coefficient of apparent total tract digestibility of dry matter and gross energy, but not crude protein of field pea grain. Cold-pelleting increased (P < 0.05) digestible energy and calculated net energy values of field pea grain, and the coefficient of apparent ileal digestibility of dry matter, gross energy and starch. Extrusion increased (P < 0.05) the coefficient of standardised ileal digestibility of threonine, tryptophan, valine, serine and tyrosine of field pea grain. In conclusion, cold-pelleting reduced TIA and increased the energy value of field pea grain, and extrusion reduced TIA and increased ileal digestibility of some amino acids compared with raw field pea grain fed to weaned pigs.